Load break device for enclosed cutouts



April 26, 1955 R. A. WISE LOAD BREAK DEVICE FOR ENCLOSED CUTOUTS Filed May 27, 1955 Inventor FQQJoePt A.Wise,

by @MP ha; |-lis Attorney.

United States Patent LOAD BREAK DEVICE FOR ENCLOSED CUTOUTS Robert A. Wise, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application May 27, 1953, Serial No. 357,867

2 Claims. (Cl. 200-446) This invention relates to a load break device, and more particularly, to a load break device for enclosed cutouts.

In some conventional forms of enclosed cutouts the load is broken merely by opening of the cutout door to separate the contacts. When the contacts become separated there is arcing between the spaced contacts. This arcing will sometimes persist even though the door is fully opened and the contacts are spaced from each other by a considerable distance. In such eventuality, even though the door is fully opened the load is not broken as long as the arc exists. To snuff out the arc the lineman can attempt to fan the arc with his cap or the like thereby cooling the arc and putting it out, or the lineman can reclose the door and try to break the load again. Obviously, such improvision is highly dangerous to the lineman. Also, arcing between the contacts will ultimately destroy them and the adjacent cutout parts.

In some other conventional forms of enclosed cutouts auxiliary load break structure is incorporated into the cutout. However, such auxiliar} structure complicates the cutout, is costly, and not always reliable.

It is an object of this invention to provide a simple, low cost, and reliable load break device for an enclosed cutout.

In a cutout having two main contacts engageable and disengageable with each other to make and break an electrical circuit, my invention comprises means for prohibiting arcing between said main contacts when said main contacts are disengaged to break said circuit, comprising an arc chamber having arc interrupting means therein, two delayed opening arcing contacts electrically connected to said main contacts and making and breaking contact within said are chamber, said arcing contacts becoming disengaged after said main contacts are disengaged, whereby an arc struck between said arcing contacts will be put out by said are interrupting means.

In an enclosed cutout having a housing with a door pivoted thereon, said door carrying an upper main movable contact engageable and disengageable with an upper stationary contact in said housing to close and open respectively an electrical circuit by closing and opening said door respectively, my invention comprises a load break device for opening said circuit and prohibiting arcing between said main contacts, comprising an arc chute in the upper portion of said housing, a second movable contact electrically connected to said main movable contact and movable in said are chute, a second stationary contact in said are chute electrically connected to said main stationary contact, said second contacts engaging and disengaging each other when said door is closed and opened respectively, said second contacts disengaging each other when said door is opened after said main contacts become disengaged, said are chute having arc interrupting means therein, whereby an arc struck across said second contacts will be put out by said are interrupting means.

The invention will be better understood by considering the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing, Figure 1 is a side view, partly in section, of an enclosed cutout embodying my invention. Figure 2 is a partial front view of the enclosed cutout embodying my invention. Figure 3 is a partial 2,707,219 Patented Apr. 26, 1955 side view, partly in section, of the enclosed cutout embodying my invention showing the relative positions of the main cutout and arcing contacts after the door of the cutout has been opened to break the load.

Referring now to the drawing, and most particularly to Figure 1, shown therein is an enclosed cutout 1 embodying my invention. The cutout 1 comprises a porcelain or other insulating material housing or bOX 2 closed by a plastic or other insulating material door 3. The door 3 is pivoted on the housing 2 for opening and closing movement about pivot point or trunnions 4 carried by housing 2. The outside of the door has an eyelet handle 5 thereon adapted to receive the end of a switchstick or the like so that the door can be opened and closed.

The inside of the door 3 has two brackets 6 and 7 thereon. These brackets have appropriate longitudinally aligned circular openings therethrough adapted to receive a fuse tube 8 for mounting on the door 3. The fuse tube 8 has an upper main movable contact portion 9 thereon adapted to be engaged or grasped by a clip-like or U-shaped main stationary contact 10 mounted on the back wall of housing 2.

Within the fuse tube 8 is a fuse link 11 which is in electrical contact with contact portion 9 and extends out through the bottom of the fuse tube 8 to make electrical contact with a hinge element 12. Hinge element 12 is pivoted to bracket 7 at 13. In its unfused condition the fuse link 11 is drawn up tautly and fastened to the hinge element 12 to hold said hinge element rigidly against the fuse tube 8. The door 3 with its fuse tube 8 mounted thereon is pivotally mounted with respect to the housing 2 inasmuch as the hook portions of the hingle element 12 pivotally engage trunnions 4.

The hinge element 12 has pivotally mounted thereon a spring driven movable contact arm or portion 14 which will engage a lower stationary contact terminal portion 15 which is mounted on the back wall of housing 2. The upper main stationary contact 10 is an electrical contact with an upper terminal 16. The enclosed cutout can be connected across an electrical line by connecting line wires or leads to terminals 15 and 16. Current will flow from terminal 16 to contacts 10 and 9, thence through fuse link 11 to hinge element 12, contact 14, and terminal 15. If a fault occurs on the line the fuse link 11 will fuse. With fuse link 11 broken hinge element 12 is no longer held rigidly against fuse tube 8. Therefore, the door 3 and fuse tube 8 mounted thereon is free to move slightly downwardly and outwardly pivotally about 13 while hinge element 12 pivots about 4 until the contacts 9 and 10 become disengaged. Thereafter the door is free to flip open to its fully open position and the electrical circuit through the enclosed cutout is broken.

Assuming the line is closed and it is desired to open the line, as to repair electrical equipment, this can be accomplished by opening the cutout door to break the contacts 9 and 10. However, when this is done there may be heavy arcing between the contacts 9 and 10 and this arcing may persist even if the door is fully opened. Arcing is dangerous to the lineman working on the line and will also burn and possibly destroy the enclosed cutout.

To remove arcing at the main contacts and possible destruction to the cutout, a pair of delayed opening auxiliary contacts and arc chute or chamber with are interrupting means therein is provided to break the electric circuit and put out the arc. Within the upper portion or top of housing 2 is formed an arc chute or chamber 17. As seen in Figures 1 and 2 chute or chamber 17 is a thin slot in the top inside wall of housing 1 and extends from the front of housing 2 to about the inside back wall thereof and has a narrow or thin width. Within the rear of the slot 17 is positioned a second stationary contact 18 electrically interconnected with contact 10 and terminal 16. The contacts 10 and 18 and terminal 16 may be formed into a unitary terminal contact portion 21 as shown in the drawing.

Electrically connected to the movable contact 9 is a second or auxiliary movable contact 19. Contact 19 is a flexible spring element or finger fastened to contact 9 by a fuse tube cap 20. If desired, element 19 can be an integral part of contact 9. When the door is closed the spring contact 19 will come into electrical contact with arcing contact 18, as clearly shown in Figure 1. It will be obvious that other types of movable arcing contacts can be employed, as for instance, a spring driven rigid contact portion.

Referring now to Figure 3, when the door is opened to break the load or electric circuit the contacts 9 and 10 will separate first. Since the arcing contact 19 when the door was closed was initially bent or flexed, as the door is opened to separate contacts 9 and 10 the spring arcing contact 19 will distend or straighten out. Not until after contacts 9 and 10 are clearly separated does element 19 reach its fully unflexed or distended length. Further opening of the door will disengage contacts 18 and 19. But at this point contacts 9 and 10 are separated so there is no arcing therebetween. Thus the load is broken at contacts 18 and 19 and any arcing attendant to opening of the electrical circuit occurs therebetween within the arc chamber or slot 17. The walls of arc chute 17 are lined or coated with a deionizing gas evolving compound. For instance, this compound may be a hydroxide, since hydroxides create de-ionizing gases under arcing conditions. Arcing within the chute 17 will cause the walls of the arc chute 17 to evolve a de-ionizing gas to cool and put the are out. Since the arc chute is a narrow slot, there will be some expulsive action of the gases evolved within the arc chamber which also contributes towards snufiing out of the arc between arcing contacts 18 and While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that changes and modifica tions may be made without departing from the invention, and that it is intended by the appended claims to cover all such changes and modifications as fall Within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an enclosed cutout having a box-like insulating material housing with a door mounted thereon for pivotal opening and closing movement, a main contact mounted on said door, and a main contact mounted in said housing, said main contacts engageable and dis engageable when said door is closed and opened to make and break an electric circuit, and means for preventing arcing across said main contacts when said door is opened to break said circuit, comprising an arc chamber positioned longitudinally above said main contacts and comprising a deep longitudinal slot in an upper portion of said housing, said are chamber having a narrow width and the walls of said are chamber evolving a deionizing gas under arcing conditions, a narrow arcing contact electrically connected to said main housing mounted contact extending in said chamber and disposed adjacent a rear portion thereof, a single narrow leaf spring arcing contact mechanically and electrically connected to said door mounted contact movable simultaneously therewith and extending longitudinally therefrom into said chamber, said arcing contacts engageable and disengageable when said door is closed and opened, said leaf spring arcing contact flexed when said door is closed, and unflexed when said door is opened, said arcing contacts becoming disengaged when said door is opened after said main contacts become disengaged, whereby an arc struck across said arcing contacts within said chamber when said door is opened will be extinguished by said deionizing gas evolved by said chamber walls.

2. In an enclosed cutout having a housing with a door, said housing having a main stationary contact mounted therein and said door having a main movable contact mounted thereon, said main contacts engageable and disengageable as said door is closed and opened to make and break an electrical circuit, a longitudinally extending narrow deep slot in an upper portion of said housing longitudinally above said main contacts, a single narrow stationary arcing contact electrically connected to said main stationary contact extending longitudinally therefrom into said deep slot and disposed adjacent a rear portion thereof, a single resilient spring finger movable arcing contact electrically connected to said main movable contact extending longitudinally therefrom into said deep slot for engagement with said narrow stationary arcing contact when said door is closed and delayed disengagement from said narrow stationary arcing contact when said door is opened subsequent to disengagement of said main contacts whereby when said door is opened to break said electrical circuit electrical arcing is established between said arcing contacts, said deep slot lined with a material evolving a deionizing gas when subjected to an electrical arc and the heat thereof, said lined deep slot comprising an electrical arc interrupting chamber integrally formed in said upper housing portion for extinguishing said electrical arcing established between said arcing contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,204,298 Carlisle June 11, 1940 2,308,026 Rawlins Jan. 12, 1943 2,314,693 Dickinson Mar. 23, 1943 2,351,426 Healis June 13, 1944 2,480,622 Warnock Aug. 30, 1949 2,610,276 Bayer Sept. 9, 1952 2,636,954 Hellstern Apr. 28, 1953 

